A kite is flying at a height of 60 m above the ground level. Ravi, standing at the roof of the house is holding the string straight and observes the angle of elevation of kite as \(30^\circ\). From the bottom of the same building, the angle of elevation of kite is \(45^\circ\). Find the length of the string and height of roof from the ground. (Use \(\sqrt{3} = 1.73\))